We present a technique for ray tracing dynamic scenes using the GPU. In order to achieve interactive rendering rates, it is necessary to use a spatial structure to reduce the number of ray-triangle intersections performed. Whenever there is movement in the scene, this structure is entirely rebuilt. This way, it is possible to handle general unstructured motion. For this purpose, we have developed an algorithm for reconstructing Uniform Grids entirely inside the graphics hardware. In addition, we present ray-traversal and shading algorithms fully implemented on the GPU, including textures, shadows and reections. Combining these techniques, we demonstrate interactive ray tracing performance for dynamic scenes, even with unstructured motion and advanced shading effects.